Lateral subtalar dislocation associated with a lateral malleolus and a nutcracker cuboid fracture: Case report of a rare pattern of lesion

INTRODUCTION AND IMPORTANCE: Combined fracture of the lateral malleolus and cuboid due to a lateral subtalar dislocation is an uncommon injury. Literature is scarce on this trauma association. To the best of our knowledge, this represents a new lesion pattern. Hereby we describe its mechanism, management and outcomes. CASE PRESENTATION: We report a case of a 58-year-old woman, who fell from the stairs and presented with pain and an acute deformity of the left foot and ankle. Plain radiographs and CT scan revealed a lateral subtalar dislocation with a lateral malleolus and cuboid fractures. After a failed closed reduction, the patient underwent an open reduction and fixation of the talonavicular joint. An external fixator was applied to address the cuboid fracture. The lateral malleolus was treated conservatively with 5.5 weeks of immobilization. At 38 months of follow-up, the patient scored 87% on the AOFAS ankle-hindfoot scale and returned to normal daily activity. Radiographs demonstrate signs of posttraumatic arthritis at the subtalar and talonavicular joints. CLINICAL DISCUSSION: After reduction of the lateral subtalar dislocation, addressing the nutcracker cuboid fracture was essential, since it can contribute to a flatfoot deformity. Although the patient progressed to posttraumatic arthritis, the sequelae are usually well tolerated and a good outcome was achieved. CONCLUSION: The rarity of this pattern of lesion is related to the necessary multidirectional forces. Correct management of the associated fractures is essential. Our study demonstrates a new lesion pattern of lateral subtalar dislocations, its mechanism, management and outcomes.